The present application relates to a new and improved construction of a step of an escalator or moving stairway or the like, particularly a step equipped with at least one warning device for warning the passenger that he or she has tread on a danger zone of the step.
Generally speaking, the step of the escalator comprises a step body equipped with a tread surface and a front or riser surface. The step further contains two side uprights or plates, each provided with a drag roller or roll and each provided with a fixing device for connection to an endless transport means. A step band or run composed of a number of steps and two endless transport means is guided between two fixed skirt guards.
In escalators or moving stairways there exists, between the moving step and the fixedly arranged skirt guards, a latent risk of entrapment or catching of the passenger's shoe, especially when wearing light or flimsy footwear. Even in escalators of the most different types of construction shoe pinching or catching accidents occur from time to time. During these accidents, fortunately, usually only gymnastic shoes, tennis shoes, rubber or plastic boots are pulled-in between the side uprights or plates of the step and the fixed skirt guards, whereas the foot can mostly still leave the caught footwear. Such accidents usually occur when the passenger places his or her foot laterally so near to the edge of the tread surface of the step that the shoe brushes or wipes against the related fixed skirt guard positioned laterally besides the step.
Apart from the thus ensuing friction opposite to the direction of travel which prevails between the passenger's shoe and the related skirt guard, there also occurs at the escalator transition locations a relative movement with a friction transverse to the direction of escalator travel. Depending on the direction of travel of the escalator, this transverse friction occurs at the upper or lower transition locations where the risers of the steps disappear, i.e. retract, or form, i.e. deploy as the case may be. Through the action of this transverse friction light footwear especially can be pulled-in between the moving step and the fixed skirt guard.
Various inventions have become known to the art by means of which attempts were and are being made to overcome the above-described danger:
Minimizing the distance between the step and the skirt guard by means of special guide devices positioned at the step and centering the step by means of the skirt guard.
Marking of the side and rear parts of the step as danger zones by coloring or inserting different colored edge or margin strips.
Reducing the coefficient of friction by covering the skirt guard with a slide or non-friction layer, e.g. formed of "TEFLON".
Raising the side parts of the tread surface of the step, also by means of inserts, so that these will be avoided because of the uncomfortable foot position.
Fan-type swivelling or pivoting safety or protective walls positioned laterally beside the step and by means of which the relative movement between the step and the skirt guard is screened.
Positioning of safety contacts along the skirt guard, especially at a predetermined distance before the entry of the step into the comb.
A step for escalators with a safety device of this type has become known from the European Pat. No. 0,087,692, published Sept. 7, 1983. Laterally at the steps there are provided two-piece, swivelling apart, fan-type side walls that ar arranged about a common pivot over the drag or trailing roller at the side plate. In the horizontal entrance or exit zone the two side wall parts lie against the step body and conjointly rest next to each other on the axle connecting the step with the transport means. At the transition from the horizontal to the slanting or sloped runway or travel path, at the location where the step risers form or deploy, there first rises or ascends the one side wall part entrained by the neighboring leading step. This, in turn, entrains the second side wall part in a fan-type manner so as to fully cover the triangle towards the skirt guard. This triangle is formed between the tread plate of the one step and the front part of the preceding step in the region of the sloped runway or travel path. The relative movement occurring up to now between the moving step and the fixed skirt guard is thus transformed into a relative movement between the moving step and the side wall moving with the same speed. Thus, while the danger of lateral pinching or entrapment of the shoe is markedly reduced, it is however not rendered totally impossible.
A further construction of step for escalators and equipped with a safety device as mentioned above is disclosed in the German Pat. No. 2,161,442, published July 13, 1972. Here the lateral edge strips and the edge strips of the tread plate directed towards the front part of the neighboring step, are made of colored, differently formed inserts. The lateral insert pieces can additionally rise above or protrude beyond the tread height of the rest of the tread plate. The function of the colored edge strips is to optically indicate to the passenger those parts of the tread plate which should not be stepped upon. Additionally, the possibly raised lateral insert pieces should, when being trod upon by the passenger, result in an uncomfortable foot position and should require him or her to remove his or her foot from this area.
A disadvantage of this prior art construction exists in that when heavy passenger frequency occurs, the colored edge parts will not be noticed or will be completely non-visible and that the lateral raised edge parts of the tread plate, because of structural reasons (greater spatial requirements in the area of the upper and lower turning points covered by the entrance plates) will not be designed with such a height that the passenger will find that standing on them will actually cause an uncomfortable foot position.